Population structure and ecology of a tropical rare rhizomatous species of teosinte Zea diploperennis (Gramineae)

One of the objectives of the Sierra de Manantlán Biosphere Reserve (Jalisco, México) is the conservation in situ of the teosinte Zea diploperennis Iltis, Doebley, Guzman & Pazzi. Zea diploperennis is perennial, shade intolerant and its 1-3 m shoots are architecturally similar to maize. Clonal growth is of the phalanx type. Genets are iteroparous (modules semelparous). The demography of seven module and genet populations was studied in seven sites representing three stages of old-field succession. Seven permanent one-meter-square plots were randomly established in each site. All genets initially present and those that became established during our study were mapped and labeled according to year of establishment The magnitude of demographic fluctuations was greater in module populations. Genet population dynamics followed a seasonal rhythm with a maximum population size obtained at the onset of the rainy season. A relation was documented between percent annual mortality of a cohort and its age: the younger the cohort, the greater the mortality. This was a statistically significant relationship, Y = [sin(-0.288x + 1.657)]2 (r = 0.92, p < 0.01), where is proportion annual mortality of genets and is the age of the cohort. The maximum rates of genet mortality occurred during the rainy season when population densities were greatest. As a consequence, we postulate that competition occurs principally during the rainy season. Linear relationships were observed between rate of population increase of genets versus old-field successional stage and soil type. Those areas with poor soil (Ultisol), degraded soil or soils with similar physical characteristics could be rehabilitated by introducing Z. diploperennis. Such rehabilitation would achieve two distinct objectives, promote propagation of this rare endemic and reclaim areas that are susceptible to erosion and further degradation

Al lettore (Premessa)

Quali sono i significati che assume il bianco nell’arte contemporanea? Questa è la domanda intorno a cui è istruito il fascicolo della rivista “Il Pensiero”. Il testo di introduzione fornisce i riferimenti essenziali per illustrare il tema, da Hermann Melville a Kazimir Malevič e prova a suggerire qualche motivo di interesse nel dialogo che la filosofia ha intrattenuto con le pratiche artistiche e letterarie

Tree diversity and structure in shaded pineapple agroforestry system in Western México [estructura y diversidad arbórea en el sistema agroforestal de piña bajo sombra en el occidente de México]

Structure and perennial woody diversity in the cropping pineapple agroecosystem is described. It is developed like main component in understory of tropical subdeciduous and Quercus forest, in combinations with cultivated non-native species; revealing a characteristic agroforestry system, in western Mexico (Jalisco and Nayarit). This is an extensive cropping system of low external inputs and local technology, mainly growing on slopes from 25% to 45%, on irregular terrain and at altitudes from 67 to 610 m. We found 1 161 woody individuals from 69 species, 62 native and seven introduced species. The Fabaceae family had 11 species. The lowest and maximum richness was in Nayarit. Fisher's alfa diversity in the study area showed differences between sites and (F=7.12, ??0.001; F=7.09, ??0.0006, respectively). Shannon's index exhibited differences only in four sites of Jalisco with the lowest diversity sites in Nayarit. Beta diversity in Jalisco was different from Nayarit. Height and diameter in study area were heterogeneous, with the majority (92%) of individuals found in intermediate heights. Diameter sizes were concentrated in four structural types. Management of this diverse shaded agroecosystem contributes to tropical biodiversity conservation and also represents a pineapple sustainable management in America

Population structure and ecology of a tropical rare rhizomatous species of teosinte Zea diploperennis (Gramineae)

One of the objectives of the Sierra de Manantl�n Biosphere Reserve (Jalisco, M�xico) is the conservation in situ of the teosinte Zea diploperennis Iltis, Doebley, Guzman & Pazzi. Zea diploperennis is perennial, shade intolerant and its 1-3 m shoots are architecturally similar to maize. Clonal growth is of the phalanx type. Genets are iteroparous (modules semelparous). The demography of seven module and genet populations was studied in seven sites representing three stages of old-field succession. Seven permanent one-meter-square plots were randomly established in each site. All genets initially present and those that became established during our study were mapped and labeled according to year of establishment The magnitude of demographic fluctuations was greater in module populations. Genet population dynamics followed a seasonal rhythm with a maximum population size obtained at the onset of the rainy season. A relation was documented between percent annual mortality of a cohort and its age: the younger the cohort, the greater the mortality. This was a statistically significant relationship, Y = [sin(-0.288x + 1.657)]2 (r = 0.92, p < 0.01), where is proportion annual mortality of genets and is the age of the cohort. The maximum rates of genet mortality occurred during the rainy season when population densities were greatest. As a consequence, we postulate that competition occurs principally during the rainy season. Linear relationships were observed between rate of population increase of genets versus old-field successional stage and soil type. Those areas with poor soil (Ultisol), degraded soil or soils with similar physical characteristics could be rehabilitated by introducing Z. diploperennis. Such rehabilitation would achieve two distinct objectives, promote propagation of this rare endemic and reclaim areas that are susceptible to erosion and further degradation

Tree diversity and structure in shaded pineapple agroforestry system in Western México [estructura y diversidad arbórea en el sistema agroforestal de piña bajo sombra en el occidente de México]

Structure and perennial woody diversity in the cropping pineapple agroecosystem is described. It is developed like main component in understory of tropical subdeciduous and Quercus forest, in combinations with cultivated non-native species; revealing a characteristic agroforestry system, in western Mexico (Jalisco and Nayarit). This is an extensive cropping system of low external inputs and local technology, mainly growing on slopes from 25% to 45%, on irregular terrain and at altitudes from 67 to 610 m. We found 1 161 woody individuals from 69 species, 62 native and seven introduced species. The Fabaceae family had 11 species. The lowest and maximum richness was in Nayarit. Fisher's alfa diversity in the study area showed differences between sites and (F=7.12, α≥0.001; F=7.09, α≥0.0006, respectively). Shannon's index exhibited differences only in four sites of Jalisco with the lowest diversity sites in Nayarit. Beta diversity in Jalisco was different from Nayarit. Height and diameter in study area were heterogeneous, with the majority (92%) of individuals found in intermediate heights. Diameter sizes were concentrated in four structural types. Management of this diverse shaded agroecosystem contributes to tropical biodiversity conservation and also represents a pineapple sustainable management in America

Loss of 10p material in a child with human papillomavirus-positive disseminated bilateral retinoblastoma

The purpose of this paper is to document relationships between knowledge of plant use and indicators of modernization in Mexico. The model we are testing envisions increasing loss of plant use knowledge with increasing modernization indicated by loss of indigenous language and acquisition of nontraditional community services such as literacy and quality of housing. As predicted, we demonstrate that empirical knowledge about plant use is both more diverse and more evenly shared by people speaking an indigenous language-the Huastec-than by mestizo and Spanish-speaking indigenous populations in the Sierra de Manantlan. Our analyses also indicate that the adoption of modern community services by eight rural communities in the Sierra de Manantlan of western Mexico has had notable effects eroding traditional knowledge about useful plants in some but not all communities. From this we suggest that even though traditional knowledge about plants probably suffered a decline that accompanied loss of the indigenous language in Manantlan, traditional knowledge may be able to survive the modernization process today where such knowledge has an important role in subsistence. " 2000 The New York Botanical Garden Press.",,,,,,"10.1007/BF02907821",,,"http://hdl.handle.net/20.500.12104/42600","http://www.scopus.com/inward/record.url?eid=2-s2.0-0033945195&partnerID=40&md5=ac159c762145b351d0f97dbad5681e78",,,,,,"2",,"Economic Botany",,"18

Losing knowledge about plant use in the sierra de manantlan biosphere reserve, Mexico

The purpose of this paper is to document relationships between knowledge of plant use and indicators of modernization in Mexico. The model we are testing envisions increasing loss of plant use knowledge with increasing modernization indicated by loss of indigenous language and acquisition of nontraditional community services such as literacy and quality of housing. As predicted, we demonstrate that empirical knowledge about plant use is both more diverse and more evenly shared by people speaking an indigenous language-the Huastec-than by mestizo and Spanish-speaking indigenous populations in the Sierra de Manantlan. Our analyses also indicate that the adoption of modern community services by eight rural communities in the Sierra de Manantlan of western Mexico has had notable effects eroding traditional knowledge about useful plants in some but not all communities. From this we suggest that even though traditional knowledge about plants probably suffered a decline that accompanied loss of the indigenous language in Manantlan, traditional knowledge may be able to survive the modernization process today where such knowledge has an important role in subsistence. © 2000 The New York Botanical Garden Press

The structure and productivity of relict stands of pitaya (Stenocereus queretaroensis; Cactaceae), Jalisco, Mexico

Pitaya fruit commercialized in southern Jalisco comes primarily from anthropogenic populations. These populations are associated with archaeological sites dating between 300 B.C. and A.D. 1200. Stand structure and productivity of five anthropogenic stands contrast sharply with that of natural and cultivated stands. Individuals from a natural stand have smaller-diameter trunks and canopies and produce less fruit than anthropogenic stands. Structure and productivity of one stand may correlate with the associated archaeological occupation. Individual productivity is highly correlated with diameter of the canopy. Both men and women participate in the harvest and sale of pitaya fruit earning the same or as much as three times that paid as wage laborers